Navigating desert ants (Cataglyphis fortis) learn to alter their search patterns on their homebound journey

In navigating home, desert ants first run off a global vector estimated on their outbound journey, and then engage in systematic search consisting of ever-increasing loops interrupted by returns to the starting point of search. Desert ants (Cataglyphis fortis ; Wehner, 1983) were trained to travel 6 m down a channel to a food source. Different groups of ants were trained to return home in another channel, from distances of 6 m (control), 9 m or 12 m. Ants at the feeder were then tested in a long test channel. The measure of where the ants first turned back on a test gave an estimate of the length of the global vector calculated on their outbound trip. The median distance of search on a 5-min test gave an estimate of the centre of the search pattern. Relative to controls, the experimental ants did not increase their estimated length of global vector, but changed their search patterns, searching on average further from the start than the controls. Tests of the outbound journey, however, revealed no differences between groups. Desert ants can learn to modify their search pattern based on experience.